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February mid to long range threats discussion


Ji

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Great post.  I never believed in the seasonal trend... atmospheric memory nonsense... but the pattern is unfolding right before us.  

Atmospheric memory is pure BS. The pattern this winter has featured a stable +NAO, +AO  to at times neutral, and a general ridge in the west, but often not ideal amplitude/position. That favors storms cutting inland and to our NW. Clippers tend to go north of us anyway most of the time. The outcomes we are seeing are typical of the pattern. Cold before, and on the backside, as storms depart. Last year we had a mega -AO most of the time, and the EPO/WPO and PNA was about ideal, so even with the NAO in the wrong phase, we scored many light to moderate snow events. We also had some luck with timing. But again, that is what the (stable) pattern supported.

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Atmospheric memory is pure BS. The pattern this winter has featured a stable +NAO, +AO  to at times neutral, and a general ridge in the west, but often not ideal amplitude/position. That favors storms cutting inland and to our NW. Clippers tend to go north of us anyway most of the time. The outcomes we are seeing are typical of the pattern. Cold before, and on the backside, as storms depart. Last year we had a mega -AO most of the time, and the EPO/WPO and PNA was about ideal, so even with the NAO in the wrong phase, we scored many light to moderate snow events. We also had some luck with timing. But again, that is what the (stable) pattern supported.

 

Uhhhh, really?  From what I recall we haven't had anything but a transient -AO, let alone a "mega"  one, for the past three winters (approximately).  Now, I know a -AO doesn't necessarily translate into good blocking, but anyhow.  You are correct in terms of the EPO/PNA last winter being favorable and stable into March.  That's what truly helped us then.  We may have lucked out some with transient blocking thus we did very well comparatively.

 

On a side note, the mood in this thread is awful.  While I understand it with all the disappointments, can we please get this kind of stuff out of what's supposed to be more of a model discussion of medium-longer range threats and patterns?  It's really kind of tedious to see multiple comments about how we suck and how we're doomed.  There's already a "Panic Room" thread as well as a Banter one, can we just keep the gnashing-of-teeth comments there for the most part?

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Atmospheric memory is pure BS. The pattern this winter has featured a stable +NAO, +AO  to at times neutral, and a general ridge in the west, but often not ideal amplitude/position. That favors storms cutting inland and to our NW. Clippers tend to go north of us anyway most of the time. The outcomes we are seeing are typical of the pattern. Cold before, and on the backside, as storms depart. Last year we had a mega -AO most of the time, and the EPO/WPO and PNA was about ideal, so even with the NAO in the wrong phase, we scored many light to moderate snow events. We also had some luck with timing. But again, that is what the (stable) pattern supported.

 

no we didn't...it was pretty variable...In fact for our 2 biggest events in DC (2/12 and 3/17) it was positive....

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Uhhhh, really?  From what I recall we haven't had anything but a transient -AO, let alone a "mega"  one, for the past three winters (approximately).  Now, I know a -AO doesn't necessarily translate into good blocking, but anyhow.  You are correct in terms of the EPO/PNA last winter being favorable and stable into March.  That's what truly helped us then.  We may have lucked out some with transient blocking thus we did very well comparatively.

 

On a side note, the mood in this thread is awful.  While I understand it with all the disappointments, can we please get this kind of stuff out of what's supposed to be more of a model discussion of medium-longer range threats and patterns?  It's really kind of tedious to see multiple comments about how we suck and how we're doomed.  There's already a "Panic Room" thread as well as a Banter one, can we just keep the gnashing-of-teeth comments there for the most part?

Eh, somewhat overstated it, but we did have a solidly -AO at times, and relative to this winter, it was pretty mega. I dont think the general public would have ever been made aware of "Polar Vortex"  without the AO being pretty negative at times(and social media of course). 

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Eh, somewhat overstated it, but we did have a solidly -AO at times, and relative to this winter, it was pretty mega. I dont think the general public would have ever been made aware of "Polar Vortex"  without the AO being pretty negative at times(and social media of course). 

 

Well it is true that it may have gone negative more compared to this year (Zwyts alludes to that above, saying it was highly variable).  I thought the "Polar Vortex!!!" being significant was mostly due to a better placed and sharp +PNA ridge in the west at that time.  We've been fortunate with mostly persistent ridging in the west this year, but I don't think it has been placed as well a lot of times.

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Is that the first wave you are looking at? Cause I don't care about that one - want it washed out and gone.

right, but it is further north and stronger

compare either 0Z or 6Z GFS to the 12Z NAM for Sunday 0Z and heights are noticeably higher on the NAM and similar to the SREFs

it's the same ole' same ole'.....block stinks and the PNA breaks down right at the wrong time so that heights are flat across the country

can it change? sure, but it's replaying exactly what has happens so many times

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right, but it is further north and stronger

compare either 0Z or 6Z GFS to the 12Z NAM for Sunday 0Z and heights are noticeably higher on the NAM and similar to the SREFs

it's the same ole' same ole'.....block stinks and the PNA breaks down right at the wrong time so that heights are flat across the country

can it change? sure, but it's replaying exactly what has happens so many times

I'll add, that there's a block over AK thru Friday and then it moves north and is replaced by a closed Low in the Gulf of Alaska.....it's killing heights

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If you wanna play the NAM extrapolation game it would be congrats New England again. That makes sense with the winter we are having though. Good thing its the NAM in the long range I guess? I definitely wont be hurt by this one if it fails. I changed my mindset last week to nothing matters outside 72 hours. And I think it might payoff with this event.

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If you wanna play the NAM extrapolation game it would be congrats New England again. That makes sense with the winter we are having though. Good thing its the NAM in the long range I guess? I definitely wont be hurt by this one if it fails. I changed my mindset last week to nothing matters outside 72 hours. And I think it might payoff with this event.

TWC  says we get 5-8in

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Well it is true that it may have gone negative more compared to this year (Zwyts alludes to that above, saying it was highly variable).  I thought the "Polar Vortex!!!" being significant was mostly due to a better placed and sharp +PNA ridge in the west at that time.  We've been fortunate with mostly persistent ridging in the west this year, but I don't think it has been placed as well a lot of times.

My atmospheric memory is failing me. I believe 2013 it was pretty darn negative, at least late in winter. My main point being patterns determine the outcomes of these storms, and last year we did get lucky as well as having an amazing set up on the Pacific side. This winter the +AO/NAO is hurting us, and really underscores the importance of  those indices being in the negative phase for the MA in most winters. Not so much for NE.

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Probably not worth much but it was the first model to shift north in the last storm.

Because it comes out sooner than the other models. Pretty sure they all took that shift on the same 0z run(other than the CMC). No credit to the 84 hour NAM on that one. But yeah, not worth much.

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Every cold shot lately is modeled too strong at a distance.

 

Last Friday, my forecast temp Tuesday morning was 1.  It was 17 in reality.

 

Two days ago, my forecast low Friday was 6.  At last check it had risen to 11.  My guess is that it keeps climbing.

 

The storms might be trending north lately because the cold air is trending north of where first modeled.

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